134 lines
6.8 KiB
Markdown
134 lines
6.8 KiB
Markdown
[](https://npm-stat.com/charts.html?package=compute-scroll-into-view)
|
|
[](https://www.npmjs.com/package/compute-scroll-into-view)
|
|
[![gzip size][gzip-badge]][unpkg-dist]
|
|
[![size][size-badge]][unpkg-dist]
|
|
[![module formats: umd, cjs, and es][module-formats-badge]][unpkg-dist]
|
|
[](https://github.com/semantic-release/semantic-release)
|
|
|
|
|
|
|
|
Lower level API that is used by the [ponyfill](https://ponyfill.com) [scroll-into-view-if-needed](https://github.com/scroll-into-view/scroll-into-view-if-needed) to compute where (if needed) elements should scroll based on [options defined in the spec](https://developer.mozilla.org/en-US/docs/Web/API/Element/scrollIntoView) and the [`scrollMode: "if-needed"` draft spec proposal](https://github.com/w3c/csswg-drafts/pull/1805).
|
|
Use this if you want the smallest possible bundlesize and is ok with implementing the actual scrolling yourself.
|
|
|
|
Scrolling SVG elements are supported, as well as Shadow DOM elements. The [VisualViewport](https://developer.mozilla.org/en-US/docs/Web/API/VisualViewport) API is also supported, ensuring scrolling works properly on modern devices. Quirksmode is also supported as long as you polyfill [`document.scrollingElement`](https://developer.mozilla.org/en-US/docs/Web/API/document/scrollingElement).
|
|
|
|
## Install
|
|
|
|
```bash
|
|
npm i compute-scroll-into-view
|
|
```
|
|
|
|
The UMD build is also available on [unpkg](https://unpkg.com/compute-scroll-into-view/umd/):
|
|
|
|
```html
|
|
<script src="https://unpkg.com/compute-scroll-into-view/umd/compute-scroll-into-view.min.js"></script>
|
|
```
|
|
|
|
You can find the library on `window.computeScrollIntoView`.
|
|
|
|
## Usage
|
|
|
|
```js
|
|
// es6 import
|
|
import computeScrollIntoView from 'compute-scroll-into-view'
|
|
// or es5
|
|
const computeScrollIntoView = require('compute-scroll-into-view')
|
|
|
|
const node = document.getElementById('hero')
|
|
|
|
// same behavior as Element.scrollIntoView({block: "nearest", inline: "nearest"})
|
|
// see: https://developer.mozilla.org/en-US/docs/Web/API/Element/scrollIntoView
|
|
const actions = computeScrollIntoView(node, {
|
|
scrollMode: 'if-needed',
|
|
block: 'nearest',
|
|
inline: 'nearest',
|
|
})
|
|
|
|
// same behavior as Element.scrollIntoViewIfNeeded(true)
|
|
// see: https://developer.mozilla.org/en-US/docs/Web/API/Element/scrollIntoViewIfNeeded
|
|
const actions = computeScrollIntoView(node, {
|
|
scrollMode: 'if-needed',
|
|
block: 'center',
|
|
inline: 'center',
|
|
})
|
|
|
|
// Then perform the scrolling, use scroll-into-view-if-needed if you don't want to implement this part
|
|
actions.forEach(({ el, top, left }) => {
|
|
el.scrollTop = top
|
|
el.scrollLeft = left
|
|
})
|
|
```
|
|
|
|
## API
|
|
|
|
### computeScrollIntoView(target, options)
|
|
|
|
### options
|
|
|
|
Type: `Object`
|
|
|
|
#### [block](https://scroll-into-view.dev/#scroll-alignment)
|
|
|
|
Type: `'start' | 'center' | 'end' | 'nearest'`<br> Default: `'center'`
|
|
|
|
Control the logical scroll position on the y-axis. The spec states that the `block` direction is related to the [writing-mode](https://developer.mozilla.org/en-US/docs/Web/CSS/writing-mode), but this is not implemented yet in this library.
|
|
This means that `block: 'start'` aligns to the top edge and `block: 'end'` to the bottom.
|
|
|
|
#### [inline](https://scroll-into-view.dev/#scroll-alignment)
|
|
|
|
Type: `'start' | 'center' | 'end' | 'nearest'`<br> Default: `'nearest'`
|
|
|
|
Like `block` this is affected by the [writing-mode](https://developer.mozilla.org/en-US/docs/Web/CSS/writing-mode). In left-to-right pages `inline: 'start'` will align to the left edge. In right-to-left it should be flipped. This will be supported in a future release.
|
|
|
|
#### [scrollMode](https://scroll-into-view.dev/#scrolling-if-needed)
|
|
|
|
Type: `'always' | 'if-needed'`<br> Default: `'always'`
|
|
|
|
This is a proposed addition to the spec that you can track here: https://github.com/w3c/csswg-drafts/pull/1805
|
|
|
|
This library will be updated to reflect any changes to the spec and will provide a migration path.
|
|
To be backwards compatible with `Element.scrollIntoViewIfNeeded` if something is not 100% visible it will count as "needs scrolling". If you need a different visibility ratio your best option would be to implement an [Intersection Observer](https://developer.mozilla.org/en-US/docs/Web/API/Intersection_Observer_API).
|
|
|
|
#### [boundary](https://scroll-into-view.dev/#limit-propagation)
|
|
|
|
Type: `Element | Function`
|
|
|
|
By default there is no boundary. All the parent elements of your target is checked until it reaches the viewport ([`document.scrollingElement`](https://developer.mozilla.org/en-US/docs/Web/API/document/scrollingElement)) when calculating layout and what to scroll.
|
|
By passing a boundary you can short-circuit this loop depending on your needs:
|
|
|
|
- Prevent the browser window from scrolling.
|
|
- Scroll elements into view in a list, without scrolling container elements.
|
|
|
|
You can also pass a function to do more dynamic checks to override the scroll scoping:
|
|
|
|
```js
|
|
const actions = computeScrollIntoView(target, {
|
|
boundary: (parent) => {
|
|
// By default `overflow: hidden` elements are allowed, only `overflow: visible | clip` is skipped as
|
|
// this is required by the CSSOM spec
|
|
if (getComputedStyle(parent)['overflow'] === 'hidden') {
|
|
return false
|
|
}
|
|
|
|
return true
|
|
},
|
|
})
|
|
```
|
|
|
|
#### skipOverflowHiddenElements
|
|
|
|
Type: `Boolean`<br> Default: `false`
|
|
|
|
By default the [spec](https://drafts.csswg.org/cssom-view/#scrolling-box) states that `overflow: hidden` elements should be scrollable because it has [been used to allow programatic scrolling](https://drafts.csswg.org/css-overflow-3/#valdef-overflow-hidden). This behavior can sometimes lead to [scrolling issues](https://github.com/scroll-into-view/scroll-into-view-if-needed/pull/225#issue-186419520) when you have a node that is a child of an `overflow: hidden` node.
|
|
|
|
This package follows the convention [adopted by Firefox](https://hg.mozilla.org/integration/fx-team/rev/c48c3ec05012#l7.18) of setting a boolean option to _not_ scroll all nodes with `overflow: hidden` set.
|
|
|
|
# TypeScript support
|
|
|
|
This library ships with library definitions for TypeScript.
|
|
|
|
[gzip-badge]: http://img.badgesize.io/https://unpkg.com/compute-scroll-into-view/umd/compute-scroll-into-view.min.js?compression=gzip&label=gzip%20size&style=flat-square
|
|
[size-badge]: http://img.badgesize.io/https://unpkg.com/compute-scroll-into-view/umd/compute-scroll-into-view.min.js?label=size&style=flat-square
|
|
[unpkg-dist]: https://unpkg.com/compute-scroll-into-view/umd/
|
|
[module-formats-badge]: https://img.shields.io/badge/module%20formats-umd%2C%20cjs%2C%20es-green.svg?style=flat-square
|